package com.dailywork.java8;

import java.util.Arrays;
import java.util.List;

/**
 * @author Benjamin Winterberg
 */
public class Streams11 {

    static class Person {

        String name;
        int age;

        Person(String name, int age) {
            this.name = name;
            this.age = age;
        }

        @Override
        public String toString() {
            return name;
        }
    }

    public static void main(String[] args) {
        List<Person> persons =
                Arrays.asList(
                        new Person("Max", 18),
                        new Person("Peter", 23),
                        new Person("Pamela", 23),
                        new Person("David", 12));

        //        test1(persons);
        //        test2(persons);
        //        test3(persons);
        //        test4(persons);
        //        test5(persons);
        test6(persons);
    }

    private static void test1(List<Person> persons) {
        persons.stream()
                .reduce((p1, p2) -> p1.age > p2.age ? p1 : p2)
                .ifPresent(System.out::println); // Pamela
    }

    private static void test2(List<Person> persons) {
        Person result =
                persons.stream()
                        .reduce(
                                new Person("", 0),
                                (p1, p2) -> {
                                    p1.age += p2.age;
                                    p1.name += p2.name;
                                    return p1;
                                });

        System.out.format("name=%s; age=%s", result.name, result.age);
    }

    private static void test3(List<Person> persons) {
        Integer ageSum =
                persons.stream().reduce(0, (sum, p) -> sum += p.age, (sum1, sum2) -> sum1 + sum2);

        System.out.println(ageSum);
    }

    private static void test4(List<Person> persons) {
        Integer ageSum =
                persons.stream()
                        .reduce(
                                0,
                                (sum, p) -> {
                                    System.out.format("accumulator: sum=%s; person=%s\n", sum, p);
                                    return sum += p.age;
                                },
                                (sum1, sum2) -> {
                                    System.out.format("combiner: sum1=%s; sum2=%s\n", sum1, sum2);
                                    return sum1 + sum2;
                                });

        System.out.println(ageSum);
    }

    private static void test5(List<Person> persons) {
        Integer ageSum =
                persons
                        .parallelStream()
                        .reduce(
                                0,
                                (sum, p) -> {
                                    System.out.format("accumulator: sum=%s; person=%s\n", sum, p);
                                    return sum += p.age;
                                },
                                (sum1, sum2) -> {
                                    System.out.format("combiner: sum1=%s; sum2=%s\n", sum1, sum2);
                                    return sum1 + sum2;
                                });

        System.out.println(ageSum);
    }

    private static void test6(List<Person> persons) {
        Integer ageSum =
                persons
                        .parallelStream()
                        .reduce(
                                0,
                                (sum, p) -> {
                                    System.out.format(
                                            "accumulator: sum=%s; person=%s; thread=%s\n",
                                            sum, p, Thread.currentThread().getName());
                                    return sum += p.age;
                                },
                                (sum1, sum2) -> {
                                    System.out.format(
                                            "combiner: sum1=%s; sum2=%s; thread=%s\n",
                                            sum1, sum2, Thread.currentThread().getName());
                                    return sum1 + sum2;
                                });

        System.out.println(ageSum);
    }
}
